Aluminum rolling oil



United States Patent Ofice 3,459,663 Patented Aug. 5, 19 69 7 Claims ABSTRACT OF THE DISCLOSURE A hot aluminum rolling oil is prepared from 98 wt. percent water and 2 wt. percent of a soluble oil which contains 72-92% of a napthenic oil having viscosity at 100 F. of 35-300 SUS, 1-5% of a trihydrocarbylphosphate such' as tricresylphosphate, 0.25-3% of an alkylamine salt of mercaptothiazole such as a nonylamine salt of 2- mercaptobenzothiazole, 2-8% of an ethyoxylated fatty amine such as soy bean amine ethoxylated with 15 moles of ethylene oxide, and 4-12% of an unsaturated fatty acidsuch as oleic acid. This emulsion when used on merchant mills in the hot rolling of aluminum and aluminum alloys prevents pick-up and maintains the rolls at lower temperatures than generally possible with other available rolling oils.

BACKGROUND OF THE INVENTION The invention relates to improved lubricants for use in hot rolling of aluminum and aluminum alloys.

When hot rolling aluminum and aluminum alloys, lubricants are employed to decrease friction between the metal and the rolls of the rolling mill. These lubricants also serve as heat transfer fluids to remove heat generated in the rolls in the metal during working since the temperature encountered during hot rolling of aluminum is in the range of from about 300 F. to about 900 F. One of the most troublesome, problems encountered in rolling aluminum and aluminum alloys is the so-called metal pick-up. This phenomena is the appearance of nodules or accretions of the light metal torn from the surfaces of the worked material and picked up by the surfaces of the 'rolls. This pick-up of metal causes marring of the finished product and sticking of the finished product to the rolls of the mill.

Straight mineral oils or composite mineral oils, although possessing adequate lubricant properties, are not adequate as coolants and, moreover, they tend to decompose "causing heavy staining of the rolled material. The best colant would be water, however water itself does not possess adequate lubricating properties.

Thus, to take advantage of the lubricating properties of oil and the cooling properties of water, emulsions of oil and water have been tried for this purpose.

Although the emulsions have been good coolants, they are not entirely satisfactory in regard to metal pick-up and staining. Y

The compositions of the present invention are improved soluble oils and the emulsions prepared therefrom. It has been found that the soluble oils of the invention need be employed only in the amount of 2-3 wt. percent in oil-in-water emulsions as opposed to generally twice this amount in prior emulsions. Another problem that has'beenencountered in hot rolling aluminum has been the over effectiveness of the lubricant so that there is actuallydifiiculty in starting the hot aluminum into the rolls. Generally this difficulty is overcome by flashing off a portionof the lubricant on the aluminum with kerosene which is a dangerous and noxious process. The emulsions'of the present invention do not require this degreasing and aluminum coated therewith is readily taken into the rolls of the miling machine.

SUMMARY OF THE INVENTION The compositions of the present invention which include the soluble oils and the emulsions prepared therefrom are not susceptible to the failings of other hot rolling aluminum and aluminum alloy lubricants. No appreciable staining has been noted on aluminum worked with-these emulsions nor is pick-up a problem. The cooling effectiveness of the emulsions is readily ascertainable due to the fact that they contain as much as 98% water.

The soluble oils comprise 72-92 wt. percent naphthenic base mineral oil having a viscosity at 100 F. of 35-300 SUS to which is added 1-5 wt. percent trihydrocarbyl phosphate, 0.25-3 wt. percent of amine salt of mercaptothiazole, 2-8 wt. percent of ethoxylated fatty amine, and 4-12 wt. percent of free unsaturated fatty acid.

DESCRIPTION OF THE INVENTION The base oil to which the other materials are added is naphthenic oil preferably a distillate oil which has been derived from a naphthenic based crude oil, Le, a crude oil having a viscosity gravity constant of about 0.86 and having a viscosity at 100 F. of 35 to 300 SUS preferably 70-150 SUS.

To this oil is added 1-5 wt. percent trihydrocarbyl phosphate, 0.25-3 wt. percent of an amine salt of mercaptothiazole, 2-8 wt. percent of an ethoxylated fatty amine and 4-12 wt. percent of a free unsaturated fatty acid. 2-3 wt. percent of this oil composition is then dispersed in water to make the emulsion.

structural The trihydrocarbyl phosphate has the formula wherein R R and R are each seletced from the group consisting of alkyl, aryl, alkaryl, and aralkyl radicals containing 6-18 carbon atoms. Examples of such radicals are heXyl, octyl, decyl, dodecyl, tridecyl, cetyl, octadecyl, phenyl, tolyl, benzyl and the like. Some compounds containing these radicals which are suitable for use in the composition of the invention are tri-o-cresyl phosphate, tri-p-cresyl phosphate, cresyl-diphenyl phosphate, benzyl diphenyl phosphate, triphenyl phosphate, trioctyl phosphate, tridecyl phosphate, decyl diphenyl phosphate and the like.

The amine salt is the reaction product of a mercaptothiazole and primary or secondary fatty amine. The mercaptothiazole has the structure where R and R" are selected from the group consisting of R and R" as a fused bivalent radical of the structure hydrogen, alkyl groups having 1-6 carbon atoms and aryl groups having 6-10 carbon atoms. Examples of suitable alkyl and aryl groups are methyl, ethyl, pentyl, hexyl, isobutyl, phenyl, and naphthyl. Some of the compounds within the structural formula are Z-mercaptothiazole, Z-mercaptobenzothiazole, 4-ethyl-2-mercaptothiazole, S-methyl-Z-mercaptothiazole, 4-hexyl-2-mercaptothiazole, 4-phenyl-2-mercaptothiazole. Mercaptoarylthiolzoles such as mercaptobenzothiazole are particularly suitable but others can be used. The fatty amine has the formula where R, and R are each selected from the group consisting of hydrogen and an alkyl radical having 8-16 carbon atoms, provided at least one of R or R is an alkyl group. Primary amines are preferred. Suitable radicals for R and R include for example, octyl, nonyl, decyl, dodecyl, tetradecyl, and hexadecyl. Some fatty amines that can be employed are octylamine, nonylamine, decylamine, dodecylamine, ditetradecylamine and the like.

The amine salts can be prepared for example by bringing together the respective reactants. Since the fatty amines specified above are either liquids or low-melting solids, little or no external heating of the reactants or reaction mixture is required. The reaction, once initiated, however, is exothermic and the temperature of the reaction mixture rises during the course of the action. For example, the nonylamine salt of Z-mercaptobenzothiazole is prepared by adding one mole of Z-mercaptobenzothiazole to one mole of a nonylamine at a temperature of 80 F. At room temperature the nonylamine is liquid. No additional heat is needed once the reaction is started since it is exothermic. Heat was evolved upon addition of the 2-mercaptobenzothiazole; the reaction was conducted in a water bath to prevent overheating. The reaction mixture was stirred for about half an hour and the mixture cooled to obtain a homogeneous, syrupy, dark amber, single-phase liquid product.

The ethoxylated fatty amines are tertiary amines which are prepared by the condensation of ethylene oxide with a fatty amine. Suitable fatty amines have from 12 to 18 carbon atoms and are condensed with from 2-15 moles of ethylene oxide per mole of amine. Preferably soy bean amines condensed with 10-15 moles of ethylene oxide are employed. The soy bean amines ethoxylated with 10-15 moles of ethylene oxide are preferred because although these materials are cationic in nature, the increasing ethylene oxide content causes them to behave more like non-ionics. This causes a certain amount of instability which is a desirable and essential feature of hot rolling aluminum emulsions.

Suitable unsaturated fatty acids have from 12 to 24 carbon atoms and include for example, lauroleic, palmitoleic, oleic, brassidic, tall oil, and the like. Two preferred acids are oleic acid and tall oil acid which contains a high percentage of unsaturated fatty acids. There is a relationship between the free fatty acid and the ethoxylated fatty amine so that as the ethylene oxide content is increased there must be a corresponding increase in the concentration of free unsaturated fatty acid Within the ranges specified. This is necessary to maintain the rather delicate balance of the emulsion stability. In the preferred compositions which contain 10-15 moles of ethylene oxide per mole of fatty amine, the free acid is present in the range of 8-10 wt. percent of the soluble oil. These compositions have the most desirable degree of stability in emulsion for use in rolling hot aluminum.

The soluble oil of the invention is prepared by blending the components described above in the ranges and proportions indicated into the oil at a temperature of 60 to 180 F. This soluble oil may be stored for indefinite periods prior to preparation of the milling emulsion which is prepared by adding to water, 2-3 wt. percent of the soluble oil based on the weight of the total emulsion. The emulsions are sufliciently stable to be stored in drums or containers for up to 6 months prior to use. The following example is submitted to show the nature of the milling operation employing a composition according to the present invention.

Ex p

A soluble oil was prepared by adding 2 wt. percent of tricresylphosphate, 1 wt. percent of a nonylamine salt of Z-mercaptobenzothiazole, 4 wt. percent of soy bean amine ethoxylated with 15 moles of ethylene oxide, 10 wt. percent oleic acid to 83 wt. percent of a distillate naphthenic base oil having a viscosity at F. of SUS and heating at 100 F. to dissolve all of the components in the oil. A 2% emulsion of this soluble oil was made in water. This emulsion was then tested ona 2 2 and a series of 12" commercial merchant mills in the hot rolling of aluminum and various alloys. The oil was tested for about 1 month on a 24-hour, six-day a week basis. Milling temperatures varied in the range of 700 to 900 F. A variety of aluminum alloys including a very difiicult to handle lead bismuth alloy were rolled successfully without excessive slippage. The 2% emulsion of the invention gave cleaner metal and rolls and brighter metal than achieved with the commercially available 4% emulsion previously employed. The emulsion of the invention also gave cooler rolls and bearings than prior oils which will extend the useful life of the mills.

The emulsion of the invention tolerated large additions of water to compensate for evaporation without loss of stability or performance. A total of three drums of soluble oil of the invention was used in a two-week period whereas experience has shown that the previously used commercial 4% emulsion would have required at least seven drums for the same period.

Samples of the first four days production were anodized and no signs of pick-up were detected by metallurgical examination.

The invention claim is:

l. A soluble oil composition comprising (1) 72-92 wt. percent of napthentic oil having viscosity of 35-300 SUS at 100% F.,

(2) 1-5 wt. percent of tryhydrocarbyl phosphate having the structural formula tothiazole which is the reaction product of mercaptothiazole having the structure n /CSH R"CS I where R and R" are selected from the group consisting of R and R" as a fused bivalent radical of the structure hydrogen, alkyl groups having 1-6 carbon atoms and aryl groups having 6-10 carbon atoms and fatty amine having the formula where R, and R are each selected from the group consisting of hydrogen and an alkyl radical having 8-16 carbon atoms, provided at least one of R or -R is an alkyl radical,

(4) 2-8 wt. percent of ethoxylated fatty amine having 12 to 18 carbon atoms in the fatty amine and 2-15 moles of ethylene oxideper mole of fatty amine, and

(5) 4-12 wt. percent of unsaturated fatty acid having 12-24 carbon atoms.

2. A soluble oil composition according to claim 1 wherein the ethoxylated fatty amine is soy bean amine and 10-15 moles of ethylene oxide.

3. A soluble oil composition according to claim 2 wherein there is 8-10 wt. percent unsaturated fatty acid.

4. A hot rolling emulsion for aluminum and aluminum alloys comprising 97-98 wt. percent Water and 2-3 Wt. percent of a soluble oil according to claim 1.

5. A hot rolling emulsion according to claim 4 wherein the fatty amine is soy bean amine and 10-15 moles of ethylene oxide.

6. A hot rolling emulsion according to claim 5 wherein there is 8-10 wt. percent unsaturated fatty acid.

7. A hot rolling emulsion according to claim 6 consisting essentially of an oil having a viscosity at 100 F. of

References Cited UNITED STATES PATENTS 2,559,584 7/1951 Barker 25249.5 X 3,255,108 6/1966 Wiese 2S2-49.5 3,311,557 3/1967 Schiermeier et a1. 252-495 X 3,371,047 2/1968 Brunel 25249.5 X

DANIEL E. WYMAN, Primary Examiner W. CANNON, Assistant Examiner US. Cl. X.R. 

